-
Asked by bobchelsea to Mark, Matthew, Mike, Paul, Sabina on 13 Mar 2014.
Question: will the sun ever go out?
- Keywords:
-
Sabina Hatch answered on 13 Mar 2014:
Eventually yes. It is burning up it’s fuel by undergoing a thermal nuclear reaction: hydrogen is fused into helium giving off energy. But there is a limited amount of hydrogen and when it has exhausted it, it cannot get anymore. What happens next depends on the size of the star.
-
Mike Lee answered on 13 Mar 2014:
The sun will go out long after life on earth dies because the sun becomes too hot. The sun is constantly getting hotter as it burns.
The earth is around 3500 million years old, it has 500 million years to go, until life dies because the sun is too hot. This means that, if the earth was to live to 100 years old, it would be 80 years old just now.
-
Paul Coxon answered on 13 Mar 2014:
The sun produces all its light and heat by fusing hydrogen into helium, releasing lots of energy. In about 1.2 billion years, the hydrogen fuel will run out and the sun will start to die. The internal core of the sun will collapse, and heat up, until it is hot enough to fuse helium into carbon.
Eventually the pressure will increase and the sun will expand to almost in size and become a red giant. It will stay like this for around 700 million years then grow larger again while becoming dimmer. After this the outer layer of the sun will blow off and the sun will keep on expanding until it’s over 166x the size it is today. Mercury and Venus will be engulfed and the Earth’s surface will melt.
The sun will get a little bigger until all the helium and hydrogen is gone and then the surface size will increase and decrease rapidly. Each expansion throws off more material and the sun loses more and more mass. Eventually, all that remains is a very hot core which slowly cools down until no heat is left.
-
Mark Jackson answered on 15 Mar 2014:
It will, but not for a long time, about 5.4 billion years. It will then turn into a red giant, possibly becoming so large that it will engulf Earth! It then becomes a white dwarf. Until then we will learn to use it more efficiently. The most efficient would be to construct a Dyson Sphere, as I explain at http://goo.gl/tSUG8v.
-
Matthew Malek answered on 19 Mar 2014:
Like any star, the Sun is locked in a long-term game of “tug-of-war” between two forces. The Sun has a lot of mass, and gravity pulls things with mass together. So gravity is trying to make the Sun collapse. In the centre of the Sun, nuclear fusion is making helium out of hydrogen, creating light and heat (and neutrinos) which radiate outwards. The size of the Sun — and any star — is the balancing point between this pull inwards and this push outwards.
The Sun has been burning hydrogen into helium for about five billion years. It has enough hydrogen inside to keep this up for about another four billion years. When it runs out, gravity will “win” and the Sun will start to collapse.
As the Sun collapses, it will heat up. Things get hot when they get compressed. When it gets hot enough, the helium will “ignite” and a new nuclear fusion process will start, buring helium into things like carbon and oxygen.
(Actually, you might be interested in knowing that all the elements heavier than hydrogen and helium and maybe a bit of lithium were produced in the heart of stars!)
When this helium burning happens, the size of the Sun will change, as there will be a new balance between the outward radiation pressure and the gravitational pull. At this point, the Sun will be a type of star known as a “red giant”. It will be so big that it will extend out past the Earth, consuming our planet, as well as Venus and Mercury.
For a really massive star, it eventally explodes in a supernova when it runs out of all possible fuel to burn. That’s pretty awesome! For a medium sized star, like our Sun, it wil simply cool off when there is nothing left to burn, and it will become something called a “white dwarf” star.
Nice question — thanks for asking! 🙂
Comments